Control mechanism for hydraulic presses



April 30, 1929. w. ERNST CONTROL MECHANISM FOR HYDRAULIC PkESSES Filed Dec. 8, 1926 2 Sheets-Sheet l Apri1130, 1929. w. ERNST CONTROL MECHANISM FOR HYDRAULIC PRESSES Filed Dec. 1926 2 Sheets-Sheet men/6221' M6661 Erna?! sition to another.

Patented Apr. 30, 1929.

UNITED STATES PATENT OFFICE.

WALTER ERNST, OF MOUNT GILEAID, OHIO, ASSIGNOR TO THE HYDRAULIC PRESS MANUFACTURING COMPANY, OF MOUNT GILEAD, OHIO.

' CONTROL MECHANISM FOR HYDRAULIC PRESSES.

Application filed December 8, 1926. Serial No. 153,410.

The invention herein disclosed. is particularly adapted for use with a hydraulic press of the character disclosed in my copending application Serial No. 138,416, filed September 29, 1926 but is adapted for use with other types of presses.

It is common to employ in hydraulic press mechanism a pump for forcing fluid under pressure to said press, which pump is of the type known as a variable stroke, variable and reversible discharge. A pump of this character may be seen for example in Patent 1,250,170 to Hole-Shaw et al. and is well known to those familiar with this art. In such pumps the direction of movement of the liquid discharged may be reversed and the speed may be varied simply by reciprocating a cross head or similar device from one po- This cross head is connected to a floating ring which may be shifted off center with relation to other elements of the pump or may be held in a central position. lVhen in a central position the pump runs idly while when the floating ring is off center on one side the fluid under pressure will bedischarged in one direction but in the opposite direction when the floating ring is moved off center on the other side.

It is unnecessary to set forth the specific construction of the pump in any more detail and the same is not illustrated herein since the present invention relates'to central mechanism interposed between the pump and the press whereby the operation of the pump will be controlled as desired.

Assuming that the press is idle and that the pump is running idly a movement of the lever adjacent the press through the interposed control mechanism will cause the pump to'deliver fluid under pressure and produce the press stroke of the platen of the press. When a certain resistance has been built up in the system the control mechanism will 0perate automatically to throw the pump into reverse and produce the return movement of the press platen. When this return movement is completed the control mechanism will be again operated to throw the pump into neutral position where it will remain with the press platen in its idle position until another pressing operation is initiated manually.

In the drawings:

Figure 1 is a side elevation of the control mechanism with the pump and press more or less diagrammatically disclosed.

Figure 2 is a view of a detail.

Figure 3 is a longitudinal section through a partof the control mechanism.

The press is herein illustrated as comprising a bed A and a top B connected by four strain rods C and having the usual table and cooperating sliding platen D operated by a main ram E. It is to be understood that this showing is merely illustrative and that various types of presses may be equipped with the control mechanism constituting the pres ent invention.

This control mechanism comprises certain elements preferably carried by the press frame which may be referred to broadly as the controlling linkage and control mechanism which may be carried by or attached to the pump proper and constitutes the control mechanism proper.

The control linkage comprises a handle 1 carried by the press frame and normally held in intermediate position by springs 2 and 3. To the handle is connected an arm 4 pivoted to a link 5, which at its other end is pivoted to an arm 6 having a hub 7 which is loosely mounted on a shaft 8 carried by the press frame. A collar 9 is fast on said shaft and the hubs 7 and 9 have interlocking project-ions cut away as indicated at 10 to provide for a certain amount of lost motion in either direction of one part relative to the other. An arm 11 is fixed to the shaft 8 and is connected by a link 12 which is preferably adjustable to an arm 13 of the control mechanism proper. The shaft 8 also has an arm 14 provided with a forked end which over lies a head 15 on a rod 16 mounted to slide in a bracket 17 carried by the press and provided with an adjustable stop collar 18 adapted to be. engaged by an arm 19 which terminates in an eye sliding on the rod 16 which arm is carried bythe platen D and will engage the stop collar 18 at a point predetermined by the adjustment of said stop collar.

If the parts are in the position shown in Figure 1 and the lever l is depressed the link 5 will be raised and the arm 6 moved upwardly, which after the lost motion is taken up,

will produce a movement of the rod 8 and. through the arm 11 and link 12 will move the control lever 13 in the direction of the arrow at and cause the pump to deliver fluid in a proper direction to initiate the pressing operation. At the termination of the downward movement of the press, the control mechanism indicated generally at F and carried by the pump G will operate to move the rod 12 ashereinafter described quickly toward the right. This will not be dangerous to the operator because-this movement will flerely vtake upsthe lost-motion and cause no ovement whatever of the lever 1 at this.

time, since this lever has already been released by the operator and has been returned 7 to its central position.

When the control mechanism as just described has been reversed, the pump then delivers fluid under pressure in adirection to return the platen D to its upper position. In this upward movement the arm 19 will ultimately contact with the collar 18 which will lift the rod 16 and through the one way connection14 and 15 will move the rod 12 toward the left in Figure 1 sufficiently to bring the control arm 13 to central position in which the pump remains idle.-

The control mechanism F through which the above sequence of operations is produced will now be described. The movable cross head of the pump is represented at 20 and attached thereto is a stem 21. This stem is mounted to slide in a sleeve 22, which is hollow throughout a portion of its length and the head 23 of the stem which bears against a spring 24 enclosed in the hollowed portion of .the sleeve 22. A stem 25 is screw threaded into the sleeve 22 'and holds the spring 24 normally under about fifty'pounds pressure.

The cbntrol lever 13 is fulcrumed at 26 to the casing ofthe control mechanism and is pivoted at 27 to the stem 25. The free end of the lever 13 is provided with a hardened portion 28 which 'is adapted to engage with a rip member 29 which is fulcrumed at 30. A strong spring 31 is coiled about the sleeve 22 and bears at one end against a fixed part and at the other .against a flange on .said sleeve and obviously tends to move the sleeve and the stem 25 toward the left as shown in Fig-v ure 3. This movement when permitted islimited by the engagement ofa collar on the stem with an adjustable stop member 32.

The fulcrum 30 of the trip 29 is connected to a small cylinder 30' which travels horizontally on slides on top of a control member F.

This cylindermay be moved and locked in desired position by means of a hand wheel 41. Trip 29 has pivoted-thereto at 33 a piston 34 which slides in the cylinder 30 and hasa head working in a chamber 35 of said cylin der. From'this chamber a pipe. 36 communicates with the main cylinder of the press so that the pressure in the chamber35 will always be the saine as that in the main presscylinder. A spring 37 bears at one end against I I the trip 29 and tends to hold it in engagement with the free end 28 of the control lever 1321s shown in Figure 3. The tension ofthis spring 37. may be adjusted by means of a hand wheel which moves the link 12 toward the left and rocks the control lever 13 about its pivot point 26 thereby moving the free end thereof toward H the right. This movement will cause the up'-.

per-end thereof to cam the trip 29 out of itsthat position. This movement of the control path after which said trip snaps into the Figure 3 position and holds the control lever 13 in lever toward the right also movesthe cross 1 head 20 and so controls the pump that fluid will be delivered under pressure to the main press cylinder. The spring 24 permits a little -7 I overtravel-of the stem 25 after the stem 21 has completed its stroke in order that the free end28may movefar enough to insure. its be: ing retained b'y'the trip 2-9.- The amount of movement of the lever 13 and the stem25 will be governed by the positionof the trip f member 29. 1 If the fulcrum 30 is moved by means of the hand wheel 41 toward the left the trip 29 will engage the control lever 13 delivering only a partial amount of the fluid and therefore imparting slower speed to thepress. This hand wheel 41 may be set for any speed desiredv t Since fluid is now being delivered under the desired pressure to the main cylinder of the press, the press platen will now move until it hits a certain resistance. The pressure in the system and consequently in the chamber 35 i will now buildup and will ultimately over-' come the tension of the spring 37 and move the piston 34 to the right, thus releasing the trip 29 from engagement with the control lever 13. The tension of this spring 37 may be varied by means of the hand wheel'39, thus varying. the pressure at, which the control mechanism will be operated and consequently 1 varying the maximum pressure to be exerted by the press, 3 K

As soon as the trip 29 releases the operating lever '13 the spring 31 will cause the stem 25 to move toward tlfe left a sufficient distance to reverse the pump and cause fluid to be discharged under' pressure .to the press for returning the platen to its normal position. The amount of this movement and consequentlythe return speed of the-press may be regulated by the feeding of the stop member 32. L

t The press will now return at this predetermined rate of speed until'thel'arm 19 contacts pump is running even if there is a leak in the system, since as soon as it starts to move downward it will release the stop collar 18 thusreleasing the controlling lever 13 and permitting the spring 31 to move the stem 21 slightly, thus moving the pump to a position to exert a certain pressure in a direction to return the platen to its upper position.

It may be noted that if the fulcrum point 30 is moved to the extreme right, the automatic feature may be eliminated since in this case the trip 29 will never engage with the lever 13 and the press will operate like an ordinary manually operated double acting cylinder. It is also noted that the trip 29 may be provided with a hand lever 40 through which it may be operated independent of the automatic mechanism it desired. It is also possible to operate the lever l by means of a pedal instead oi by hand. Various other detail changes may be made in the precise construction without in any way departing from the spirit of the invcntion, which is to be regarded as limited only by the scope of the appended claims.

I claim as my invention:

1. A control mechanism adapted to be 'operatively connected to a hydraulic circuit including a reversible variable discharge pump and a hydraulic press having a movable platen; saidmechanism comprising a device adapted to occupy three positions,- means for moving the device from the first to the second position to cause the pump to discharge so as to produce the pressing movement of the platen, pressure controlled means for thereafter moving the device from the second to the third position to reverse the discharge of the pump and produce the return movement of the platen, and automatic'means for thereafter moving .the device from the third to thefirst position to place the pump in a neutral position.

2. A control mechanism adapted to be operatively connected to a hydraulic circuit eluding a reversible variable discharge pump and a hydraulic press having a movable platen; said mechanism comprising a device adapted to occupy three positions, means for moving the device from thefirst to the second position to bring about the pressing movement of the platen, means for detaining the device in such position, means controlled by the pressure in the circuit for releasing said detaining means. and means for moving said device when released from the detaining means from the second to the third position '-to thereby vary the, position of to produce the return movement of the platen.

3. A control mechanism adapted to be operatively connected to a hydraulic circuit including a reversible variable discharge pump and a hydraulicpresshavingamovableplaten;

saidmechanism comprisingadevice adapted to occupy three positions, means for moving the device from the first to the second position to bring about the pressing movement of the platen, a spring actuated detent for detaining the device in such position, means controlled by the pressure in the circuit for releasing said detent, and spring means for moving said device when released from the detaining means from the second to the third position v to produce the return movement of the platen.

4. A controlmechanism adapted to be operatively connected to a hydraulic circuit including a reversible variable discharge pump and a hydraulic press having a movable platen; said mechanism comprising a device adapted to occupy three positions, means for moving the device from the first to the second position to bring about the pressing movement of the platen, a spring actuated detent for detaining the device in such position, means for varying the normal position of the detent to thereby vary the position of the device and the consequent speed of the press,

and means controlled by the pressure in the circuit for. releasing said detent to permit the device to move to another position.

5. A control mechanism adapted to be operatively connected to a hydraulic circuit including a reversible variable discharge pump and a hydraulic press having a movable platen; said mechanism comprising a device adapted to occupy three positions, means for ,moving the device from the first to the second position to bring about the pressing movement of the platen, means for detaining the device in such position, means controlled by the pressure in the circuit for releasing the device from the detaining means, means for moving the device when released from the second to the third position, and means for varying the third position of the device and the consequent speed of the return movement of the platen.

6. A control mechanism adapted to be operatively connected to a hydraulic circuit including a reversible variable discharge pump and a hydraulic press having a movable platen; said mechanism comprising a device adapted to occupy three positions, means forv moving the device from the first to the second position to bring aboutthe pressing movement of the platen, means for detaining the .device in such position, means for varying the normal position of the detaining means said device and the consequent speed of the the circuit for releasing the. device from the detaining means, means for moving the deplaten, means controlled by the pressurein f eratively connected to a hydraulic circuit including a reversible variable discharge pump and ahydraulic press having amovable platen; manually operable means adjacent said press for moving the device, from the first to the second position to bring about the pressing movement of the platen, means controlled bythe pressure in the circuit for moving the device from the second to the third position to produce the return movement of the platen, and means controlled by the return move ment of the platen for moving the device from the third to the first position to place the pump in a neutral position. 8. A control mechanism adapted to be operatively connected to a hydraulic circuit including a reversible variable discharge pump and a hydraulic press having a movable platen; manually operable means adjacent said press for moving the device from the first to the second position to bring about the pressing movement of the platen, means controlled by the pressure in the circuit for moving the device from the second to the third position to produce the return movement of the platen, means controlled by the returnmovement of the platen for moving the device from the third to the first position to place the pump in a neutral position, and means for varying the second and third positions of said device.

9. A control mechanism adapted to be operatively connected to a hydraulic circuit ineluding a reversible variable discharge pump having a control member and a hydraulic press having a movable laten; said mechanism comprlsing a mova le device connected to said control member, means for moving said device to a position to produce the pressing movement of the platen, a spring oper ated detent for said device, a piston connected to the detent and operated by the pressure in the circuitfor releasing said detent, and means for thereafter moving said device to a position to produce the return movement of the platen.

10. A control mechanism adapted to be' operatively connected to a hydraulic circuit including a reversible variable vdischarge pump having a control member and a hydraulic press having a movable platen; said mechanism comprising a movable deviceconnected to said control member, means for moving said device to a position to produce the pressing movement of'the platen,.a"spring operated detent for said device, a piston connected to the detent and operated by the pressure in the circuit for releasing said detent, and

means for varying the predetermined pressure at which the detent will bereleased'. r

11. A control mechanism adapted to be operatively connected to a hydraulic circuit including a reversible variable discharge pump having a control member and a hydraulic press having a movable platen; said mechanism comprising a movable device connected to said control member, means for moving said device toa position to produce the pressing movement of the platen, a spring operated detent for said device, a piston connected to the piston and operated by the pressure in the circuit for releasing said detent,

means for varying the predetermined pressure at which the detent will be released, and means for thereafter moving said device to a position to produce the return movement of the platen.

. 12. A control mechanism adapted to be operatively connected to a hydraulic circuit including a. reversible variable discharge pump and a hydraulic press having a movable platen; said mechanism comprising a lever adapted to be connected to and control said pump, a link extending from the lever to a point adjacent the'press, a rock shaft con: nected to said link, and manually operable lever-actuating means having a los motion connection with said rock shaft;

13. Acontrol mechanism adapted to be operatively connected to a hydrauliccircuit including a reversible variable discharge pump and a hydraulic press having a movable platen; said mechanism comprising a lever adapted to be connected to and control said pump, a link extending from the lever to a point adjacent the press, a rock shaft connected to said link, manually operable lever actuating means having a lost motion connection with said rock shaft, and means adapted to be operated by the movement of the platen having a one way connection with the rock shaft for moving the lever to neutral position.

14. In combination, a reversible, variable capacity pump, a double acting hydraulic v notor, means forming-with the pump and motor ahydraulic circuit, mechanism for varying the'pump capacity from zero in either direction of flow, means for moving said mechanism from zero capacity position to pumping position whereby the motor piswith the press and pump a hydraulic circuit,

and controlling means operatively connected ith'the pump and circuit for moving the p aten towards and from the table and including a control lever operatively connected with the pump for controlling the direction of fluid in the circuit, a trip for holding said lever in one extreme position for directing the fluid to move the platen towards the table, means responsive to the built up pressure in the circuit during said movement of the platen to release said trip, and means for moving the control lever to the other extreme position upon release of said trip whereby the direction of fluid in the circuit will be reversed. Y

17. The combination with a hydraulic press including a stationary table and a reciprocatory platen movable towards and from the table, of a reversible pump, means forming with the press and pump a hydraulic circuit, and controlling means operatively connected with the pump and circuit for moving the platen towards and from the table and including a control lever operatively connected with the pump for controlling the direction of fluid in the circuit, a trip for holding said control lever in one extreme position for directing the fluid to move the platen towards the table, means responsive to the built up pressure in the circuit during said movement of the platen to release said trip, said responsive means including a pressure cham-v ber operatively connected to the circuit, and

a piston in said chamber and connected to the trip, and means for moving the control lever to the other extreme position upon rei lease of said trip whereby-the direction of fluid in the circuit will be reversed.

18. The combination with a hydraulic press including a stationary table and a reciprocatory platen movable towards and from the table, of a reversible pump, means forming with the press and pump a hydraulic circuit, controlling means operatively connected with the pump and circuit for moving the platen towards and from'the table and including a control lever operatively connected with the pump for controlling the direction of fluid in the circuit, a'trip for holding said lever in one extreme position for directing the fluid tomove the platen towards the table, means responsive to the built up pressurein the circuit during said movement of the platen to release said trip, said responsive means including a pressure chamber operatively connect-ed to the circuit, and a piston in said chamber and connected to the trip, means for moving the lever to the other extreme position upon release of said trip whereby the direction of fluid in the circuit will be reversed, and means controlled by the platen for niovingthe control lever to an intermediate position for placing the pump in neutral position.

19. The combination with a hydraulic press including a stationary table and a reciprocatory platen movable towards and from the table, of a reversible pump, means forming with the press and pump a hydraulic circuit, controlling means operatively connected with the pump and circuit for moving the platen towards the table and responsive tothe pressure built up in the circuit during said movement of the platen for automatically revers- 7 ing the pump and the platen irrespective of the position of the platen relative to the table, and means connected to the controlling means and operated by the platen during the reverse movement thereof to automatically place the --in one extreme position for directing the fluid tomove the platen towards the table, means responsive to the built up pressure in the circuit during said movement of the platen to release said trip, and means for moving the control lever to the other extreme position upon release of'said trip whereby the direction of fluid in the circuit will be reversed, and means connected to the control lever and 0perated by the platen during the reverse movement thereof to automatically move the lever to an intermediate position and thereby place the pump in neutral position and stop the movement 'oithe platen at the end of one complete cycle.

i 21. The combination with a hydraulic'press including a stationary table and a reciprocatory vplaten movable towards and from the table, of a reversible pump, means forming with the press and pump a hydraulic circuit, and controlling means operatively connected with the pump and circuit for moving the platen towards and from the table and including a control'lever operatively connected with the pump for controlling the direction of fluid pump in neutral position and thereby stop platen at the end of one in the'circuit, a trip: for holding said lever in one extreme position for direc in theffluid to move the platen towards'the tab e, means responsive. to the built up pressure in the circuit during said movement of the platen to release said trip, and means for moving the control lever to the other extreme position upon release of said trip whereby the direction of fluid in the circuit willbe reversed, and means connected to the control lever and operated by the platen during the reverse moVement thereof to automatically move the lever to an intermediate position and thereby place the pump in neutral position and stop the movement of theplaten at the end of one complete cycle, and manually operable means connected to the control lever for moving the same for engagement by the trip.

In testimony whereof, I have hereunto subscribed my name.

WALTER ERNST. 

